Mud nest under rock less than one foot from the ground. There are two rows of holes where the inhabitants exited. The last image shows there is a pile of mud underneath the nest. According to Bug Guide, "This is a Sceliphron caementarium [Black and Yellow Mud Dauber] nest that has been reused by resin bees (Megachilidae)."
Rocky area on top of hill above Lake Hodges.
Ava, I remembered the mission! ;)
Lat: 33.05, Long: -117.08
Spotted on Jan 28, 2014
Submitted on Jan 29, 2014